BILE-SALTS, like cholesterol and bile-pigments, are normal constituents of bile, but while solid deposits containing cholesterol and bile-pigments, i.e. , gallstones, are common, solid deposits of bile-salts do not occur. This is because the bile-salts are very soluble in water and body fluids. The free bileacids, however, are relatively insoluble, and are readily deposited from solutions containing bilesalts if these solutions are made sufficiently acid.
Other factors, as well as a sufficient degree of acidity, are required if precipitated bile-acids are to be retained as a cohesive aggregate or stone. All the necessary factors are evidently present occasionally, for a few cases of bile-acid enteroliths are on record.
The principal bile-acids whose salts are normally present in human bile are cholic acid and deoxycholic acid ; one, which is less well known, chenodeoxycholic acid, may also be present, sometimes in appreciable amounts. It is believed that the greater part of these acids is conjugated with the amino-acids glycine and taurine, forming glyco-or tauro-cholic acid, glyco-or tauro-deoxycholic acid, etc., and it is the salts of the glyco-or tauro-acids which are usually referred to as the bile-salts. Deoxycholic acid differs from the other two in possessing to a very high degree, in its free or unconjugated form, the property of forming molecular compounds with a number of other substances. Of special importance are the compounds it forms with the higher fatty acids, particularly palmitic and stearic acids. These compounds, known as choleic acids, contain eight molecules of deoxycholic acid and one of the fatty acid. Probably most, if not all, of the unconjugated deoxycholic acid which finds its way into the intestine is in the form of choleic acid.
Enteroliths consisting mainly of choleic acid have been reported on at least ten occasions, the first by K. A. H. Morner and Sjoquist in 1908 (quoted by C. T. Morner, 1923). C. T. Morner (1939) gives